U.S. patent application number 16/115224 was filed with the patent office on 2019-03-28 for single structure multi mode antenna for wireless power transmission incorporating a selection circuit.
The applicant listed for this patent is NUCURRENT, INC.. Invention is credited to Jacob Babcock, Christine A. Frysz, Jason Luzinski, Alberto Peralta, Ajit Rajagopalan, Vinit Singh.
Application Number | 20190097461 16/115224 |
Document ID | / |
Family ID | 58053088 |
Filed Date | 2019-03-28 |
View All Diagrams
United States Patent
Application |
20190097461 |
Kind Code |
A1 |
Singh; Vinit ; et
al. |
March 28, 2019 |
SINGLE STRUCTURE MULTI MODE ANTENNA FOR WIRELESS POWER TRANSMISSION
INCORPORATING A SELECTION CIRCUIT
Abstract
An electrical system incorporating a single structure multiple
mode antenna is described. The antenna is preferably constructed
having a first inductor coil that is electrically connected in
series with a second inductor coil. The antenna is constructed
having a plurality of electrical connections positioned along the
first and second inductor coils. A plurality of terminals is
connected to the electrical connections that facilitate numerous
electrical connections and enables the antenna to be selectively
tuned to various frequencies and frequency bands.
Inventors: |
Singh; Vinit; (Austin,
TX) ; Peralta; Alberto; (Chicago, IL) ;
Rajagopalan; Ajit; (Chicago, IL) ; Luzinski;
Jason; (Chicago, IL) ; Babcock; Jacob;
(Chicago, IL) ; Frysz; Christine A.; (Orchard
Park, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NUCURRENT, INC. |
Chicago |
IL |
US |
|
|
Family ID: |
58053088 |
Appl. No.: |
16/115224 |
Filed: |
August 28, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14821157 |
Aug 7, 2015 |
10063100 |
|
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16115224 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01F 38/14 20130101;
H01F 27/38 20130101; H02J 50/10 20160201; H02J 50/12 20160201; H01F
29/02 20130101; H02J 7/025 20130101 |
International
Class: |
H02J 50/12 20160101
H02J050/12; H01F 38/14 20060101 H01F038/14; H02J 50/10 20160101
H02J050/10 |
Claims
1. An antenna, comprising: a) a substrate, comprising: i) a first
conductive wire forming a first coil having N.sub.1 number of turns
with spaced apart first and second first coil ends, wherein the
first coil is capable of generating a first inductance; ii) a
second conductive wire forming a second coil having N.sub.2 number
of turns with spaced apart first and second coil second ends,
wherein the second coil is capable of generating a second
inductance; iii) at least one terminal electrically connected to at
least one of the ends of the first and second coils; b) a selection
circuit electrically connected to the at least one terminal or at
least one of the ends of the first and second coils, wherein the
selection circuit actively monitors and measures the electrical
impedance at the respective antenna connections and combinations
thereof; and c) wherein a tunable inductance is generatable by the
selection circuit actively connecting and/or disconnecting various
regions or specific locations along the coils.
2. The antenna of claim 1 further comprising a second terminal and
a third terminal, wherein the second terminal electrically connects
to the first or second end of the second coil and a third terminal
electrically connects along either of the first or second
coils.
3. The antenna of claim 2 wherein a tunable inductance or frequency
is generatable by selecting a connection between two of the first,
second and third terminals.
4. The antenna of claim 1, wherein the selection circuit is an
electrical switch circuit.
5. The antenna of claim 4 wherein the electrical switch circuit
detects and analyzes the electrical impedance of either or
combination thereof of the first and second coils.
6. The antenna of claim 5 wherein an operating frequency of either
or combination thereof of the first and second coils is selected
based on the electrical impedance value.
7. The antenna of claim 1 wherein the selection circuit connections
generate an inductance value at a desired operating frequency or
frequencies.
8. The antenna of claim 4 wherein the electrical switch circuit is
electrically connected in series between the first and second
coils.
9. The antenna of claim 4 wherein the electrical switch circuit
selects a connection between the first or second coils, or selects
either of the first or second coils individually.
10. The antenna of claim 4 wherein the electrical switch circuit at
least one capacitor having a first capacitance.
11. The antenna of claim 1 wherein the selection circuit further
electrically connects to the second and third terminals, wherein
actuation of the selection circuit electrically connects two of the
three terminal ends so that an operating frequency is modified.
12. The antenna of claim 1 wherein the selection circuit comprises
at least one of an electrical component selected from the group
consisting of a resistor, a capacitor, and an inductor.
13. The antenna of claim 2 wherein the third terminal is
electrically connected to an electrical switch circuit comprising
at least one capacitor, wherein the electrical switch circuit is
electrically connected to the second end of the first coil and the
first end of the second coil, and wherein actuation of the
electrical switch electrically connects two of the three antenna
terminal ends so that an operating frequency is modified.
14. The antenna of claim 1 wherein each terminal has a terminal
lead portion that extends between a coil connection point and a
terminal end, the coil connection point electrically connected to
either of the first and second conductive wires of the first and
second coils, respectively.
15. The antenna of claim 14 wherein the terminal lead portion
further extends over at least a portion of either of the first and
second conductive wires of the first and second coils,
respectively.
16. The antenna of claim 1 wherein an electrical signal is selected
from the group consisting of a data signal, an electrical voltage,
an electrical current, and combinations thereof is receivable by at
least the first and second coils.
17. The antenna of claim 1 wherein an electrical signal is selected
from the group consisting of a data signal, an electrical voltage,
an electrical current, and combinations thereof is transmittable by
at least the first and second coils.
18. The antenna of claim 1 wherein the substrate material is
composed of an electrically insulative materials selected from the
group consisting of a polyimide, an acrylic, fiberglass, polyester,
polyether imide, polytetrafluoroethylene, polyethylene,
polyetheretherketone (PEEK), polyethylene napthalate,
fluropolymers, copolymers, a ceramic material, a ferrite material,
and combinations thereof.
19. The antenna of claim 1, wherein the antenna is capable of
receiving or transmitting within a frequency band selected from the
group consisting of about 100 kHz to about 250 kHz, about 250 kHz
to about 500 kHz, 6.78 MHz, 13.56 MHz, and combinations
thereof.
20. The antenna of claim 1 wherein the antenna is capable of
receiving or transmitting at frequencies of at least 100 kHz.
Description
RELATED APPLICATIONS
[0001] This application is a continuation, which claims priority to
U.S. application Ser. No. 14/821,157, filed Aug. 7, 2015, the
disclosure of which is entirely incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present disclosure relates generally to the wireless
transmission of electrical energy and data. More specifically, this
application relates to an antenna that facilitates the wireless
transmission of data and electrical energy at multiple operating
frequency bands.
BACKGROUND
[0003] Wireless energy transfer is useful in cases where the
interconnection of wires may be inconvenient, hazardous or
impossible. In recent years, applications employing near-field
wireless power and/or data transmission have gained prominence in
areas such as consumer electronics, medical systems, military
systems and industrial applications. Near-field communication
enables the transfer of electrical energy and/or data wirelessly
through magnetic field induction between a transmitting antenna and
a corresponding receiving antenna. Near-field communication
interface and protocol modes are defined by ISO/IEC standard
18092.
[0004] However, near-field communication is often not optimal
because prior art antennas that facilitate the wireless transfer of
electrical power and/or data operate inefficiently. In such cases,
the amount of electrical energy received by the corresponding
antenna is generally significantly less than the amount of
electrical energy initially transmitted. In addition, data that is
received may be incomplete or may become corrupted. In addition,
near-field communication generally suffers from reduced wireless
transfer distances, i.e., the transmission range, and physical
antenna orientation issues. These inefficiencies of near field
communication are largely due to the low quality factor of the
prior art antennas in addition to the inefficient large size of
prior art antennas. In general, prior art near field communication
antennas have a relatively large size that hinders efficient
operation and wireless transmission. Size and efficiency are often
a tradeoff, a problem which becomes more acute when multiple
wireless operations are desired, i.e., multiple modes of operation.
A solution to inefficient near-field communication is antenna
integration.
[0005] Inductive solutions transfer power and/or data between two
inductor coils that are placed in close proximity to each other.
This technology, for example, facilitates the deployment of
inductive charging "hot spots" that enables wireless electrical
charging of electronic devices by simply placing them near a
charging "hot spot", such as on a surface of a table. However, for
these systems to operate efficaciously, the respective transmitter
and receiver antennas are required to not only be located in close
proximity to each other but, in addition, must also be physically
positioned in a specific orientation with respect to one another.
Typically, these prior art antennas require that they are
physically positioned in near perfect alignment such that the
centers of the respective transmitting and receiving antennas are
oriented in perfect opposition to each other in order to operate
efficaciously. This general requirement for near perfect physical
alignment of the transmitting and receiving antennas typically
leads to poor near field communication performance as it is
challenging to achieve perfect alignment of the opposing
transmitting and receiving antennas to ensure proper wireless power
and/or data transfer.
[0006] As a result, use of these prior art antennas leads to near
field communication that is generally not reliable and
significantly reduced operating efficiency. As defined herein
"inductive charging" is a wireless charging technique that utilizes
an alternating electromagnetic field to transfer electrical power
between two antennas. "Resonant inductive coupling" is defined
herein as the near field wireless transmission of electrical energy
between two magnetically coupled coils that are part of two spaced
apart resonant circuits that are tuned to resonate at the same
frequency. "Magnetic resonance" is defined herein as the excitation
of particles (as atomic nuclei or electrons) in a magnetic field by
exposure to electromagnetic radiation of a specific frequency.
[0007] Various multimode wireless power solutions have been
developed to address these antenna positioning and proximity
limitations and concomitant of reliability & efficiency issues.
In some cases, operating frequency bands have been reduced, for
example, a frequency band that ranges from about 150 kHz to about
250 kHz to increase range from about 15 mm to about 20 mm has been
achieved by resonating the receiving antenna at a frequency that is
about the same as the frequency of the transmitting antenna, both
of which are similar to the frequency at which power transfer is
taking place. However, such solutions have not sufficiently
addressed the need to provide increased efficient wireless transfer
with multiple mode operation capability through modification of the
antenna structure.
[0008] Inductive and resonance interface standards have been
developed to create global standards for wireless charging
technologies. "Qi" is a wireless inductive power transfer
standard/specification. Specifically, the Qi wireless inductive
power transfer standard is an interface standard that was developed
by the Wireless Power Consortium. The Qi interface standard is a
protocol generally intended to facilitate transfer of low
electrical power up to about 15 W at frequencies ranging from 100
kHz to about 200 kHz over distances ranging from about 2 mm to
about 5 mm.
[0009] "Rezence" is a competing interface standard developed by the
Alliance for Wireless Power (A4WP) for wireless electrical power
transfer based on the principles of magnetic resonance.
Specifically, the Rezence interface standard currently supports
electrical power transfer up to about 50 W, at distances up to
about 5 cm. Unlike the Qi interface standard, the Rezence interface
standard utilizes an increased frequency of about 6.78 MHz+/-15
kHz.
[0010] In addition, there exists a third standard developed by the
Power Matters Alliance (PMA) that operates in the frequency range
of about 100 kHz to about 350 kHz. Unlike prior art multi-band
antennas, the multi-band single structure antenna of the present
disclosure is capable of receiving and/or transmitting signals
and/or electrical energy across all of these standards with one
antenna.
[0011] Currently these standards are the preeminent standards for
wireless power technology in consumer electronics. Although these
standards are relatively new to the market, the surge in
development of small portable wireless devices and the
proliferation of wireless transmission solutions into other
wireless applications increases the need for, and adoption of,
these standards. The Qi interface standard, released in 2010, has
already been widely adopted. The Qi interface standard is currently
incorporated into more than 20 million products world-wide.
[0012] Antennas are a key building block in the construction of
wireless power and/or data transmission systems. As wireless
technologies have developed, antennas have advanced from a simple
wire dipole to more complex structures. Multi-mode antennas have
been designed to take advantage of different wireless interface
standards. For example, Qi inductive wireless charging was first
demonstrated in an Android smartphone more than four years ago. In
2015, the Samsung.RTM. Galaxy S6.RTM. supports two wireless
charging standards, namely PMA and WPC's Qi. This solution,
however, addresses inductive interface standards only. Given the
differences in, for example, performance efficiencies, size,
transfer range, and positioning freedom between inductive
transmission versus resonance-based transmission, what is needed is
a single antenna board that works with all types of wireless
charging standards, for example, the PMA standard, WPC's Qi
standard and A4WP's Rezence standard.
[0013] Furthermore, some wireless transmission applications will
utilize a combination of standards-based and/or non-standards-based
transfer protocols. The multi-band single structure antenna of the
present disclosure is capable of receiving and/or transmitting
signals and/or electrical energy across any combination of
standards-based and/or non-standards-based transfer protocols with
one antenna.
[0014] Prior art "multi mode" antennas, referred to as
"Two-Structure Dual Mode" (TSDM) antennas, are typically
constructed having two discrete antenna structures that are
positioned on a substrate. The two discrete antenna structures that
comprise a TSDM antenna operate independent of each other and
require separate terminal connections to each of the respective
independent antenna. FIG. 1 illustrates an example of such a prior
art two-structure dual mode antenna 10 which comprises a first
exterior inductor 12 and a second, separate interior inductor 14,
each antenna having a positive and negative terminal connection
respectively that are not electrically connected. However, such
TSDM antennas have a relatively large footprint which comprises a
significant amount of space and surface area. Such TSDM antennas
are therefore, not ideally suited for incorporation with small
electronic devices or positioned within small confined spaces.
[0015] Two-structure multi-mode (TSMM) antennas 10 are generally
constructed such that both the separate exterior and interior
inductors 12, 14 each have a specific inductance. Thus, the
exterior inductor 12 is constructed having a specific number of
exterior inductor turns and the interior inductor 14 is constructed
having a specific number of interior inductor turns. In this
structure, the two respective coils operate as independent
antennas. Coil-based TSMM antennas fundamentally require a large
amount of area to enable better performance. Specifically, antenna
coupling between the exterior and interior antennas require that
they be positioned a distance away from each other such that energy
generated from one antenna is not absorbed by the other.
Furthermore, in a traditional TSMM configuration, when the
"interior" antenna is operating, the area extending from the
outermost trace of the internal antenna to the outermost trace of
the exterior antenna is not being utilized and, thus, is "wasted"
space.
SUMMARY
[0016] The present disclosure provides various embodiments of an
antenna that is capable of wirelessly receiving and/or transmitting
electrical power and/or data between different locations.
Specifically, the antenna of the present disclosure is designed to
enable wireless reception or transmission of electrical power
and/or data over multiple frequencies such as the specifications
established by the Qi and Rezence interface standards, as
previously mentioned. The multi-mode antenna of the present
disclosure is of a single structure comprising at least two
inductor coils that are electrically connected in series. In an
embodiment, the single structure multi-mode antenna of the present
disclosure may comprise a composite of at least one substrate on
which at least one electrically conductive filar is disposed.
Furthermore, at least one of the substrate layers that comprise the
single structure antenna may be composed of a different material.
Alternatively, the single structure antenna of the present
disclosure may be constructed without a substrate.
[0017] The single structure antenna of the present disclosure
preferably comprises at least two inductor coils that are
electrically connected in series. Each of the inductors is
preferably composed of an electrically conductive material such as
a wire, which may include, but is not limited to, a conductive
trace, a filar, a filament, a wire, or combinations thereof. It is
noted that throughout this specification the terms, "wire",
"trace", "filament" and "filar" may be used interchangeably. As
defined herein, the word "wire" is a length of electrically
conductive material that may either be of a two dimensional
conductive line or track that may extend along a surface or
alternatively, a wire may be of a three dimensional conductive line
or track that is contactable to a surface. A wire may comprise a
trace, a filar, a filament or combinations thereof. These elements
may be a single element or a multitude of elements such as a
multifilar element or a multifilament element. Further, the
multitude of wires, traces, filars, and filaments may be woven,
twisted or coiled together such as in a cable form. The wire as
defined herein may comprise a bare metallic surface or
alternatively, may comprise a layer of electrically insulating
material, such as a dielectric material that contacts and surrounds
the metallic surface of the wire. A "trace" is an electrically
conductive line or track that may extend along a surface of a
substrate. The trace may be of a two dimensional line that may
extend along a surface or alternatively, the trace may be of a
three dimensional conductive line that is contactable to a surface.
A "filar" is an electrically conductive line or track that extends
along a surface of a substrate. A filar may be of a two dimensional
line that may extend along a surface or alternatively, the filar
may be a three dimensional conductive line that is contactable to a
surface. A "filament" is an electrically conductive thread or
threadlike structure that is contactable to a surface.
[0018] In a preferred embodiment, the at least two inductor coils
are disposed on an external surface of one of the plurality of
substrates. Alternatively, at least one of the plurality of
inductor coils may be disposed on each of the substrates that
comprise the antenna structure. At least one via may be provided
that connects at least two of the conductive materials that
comprise the inductors of the antenna. In a preferred embodiment,
the at least one via may be provided to create an electrical shunt
connection between the coils, or portions thereof. As defined
herein the term "shunt" means an electrically conductive pathway
that is created by electrically joining two points of a circuit
such that an electrical current or an electrical voltage may pass
therethrough.
[0019] The inductor coils are strategically positioned and
electrically connected in series to facilitate the reception and/or
transmission of wirelessly transferred electrical power or data
through near field magnetic induction at either, both or all
frequency ranges of about 100 kHz to about 200 kHz (Qi interface
standard), 100 kHz to about 350 kHz (PMA interface standard), 6.78
MHz (Rezence interface standard), or alternatively at a frequency
being employed by the device in a proprietary recharging mode. In
addition, the antenna of the present disclosure may be designed to
receive or transmit over a wide range of frequencies on the order
of about 1 kHz to about 1 GHz or greater in addition to the Qi and
Rezence interfaces standards.
[0020] In addition to enabling dynamic adjustment of the antenna's
operating frequency, the single structure of the present disclosure
also enables dynamic adjustment of its self-resonance frequency.
Such self resonant frequencies are typically utilized for radio
frequency (RF) communication such as a cellular phone or radio. The
single structure antenna of the present application is capable of
self resonant frequencies that range from about 1 kHz to about 500
GHz. Furthermore, the single structure antenna of the present
application is capable of dynamically adjusting the inductance
exhibited by the antenna.
[0021] Such a dynamic adjustment of at least one of the operating
frequency, resonance frequency and inductance of the antenna is
preferably accomplished through modifying the various connections
within the antenna. More specifically, the operating frequency, the
self-resonance frequency and/or the inductance of the antenna can
be changed by modifying the various "tapped" inductance coil
electrical connections that are strategically positioned
therewithin. Thus, by modifying the sequence of the electrical
connections between the at least various portions of the
electrically connected inductor coils that comprise the antenna,
the operating frequency, resonance frequency and/or inductance can
be dynamically adjusted to meet various application requirements.
Moreover, by dynamically adjusting the electrical connections
within the antenna of the present disclosure, the separation
distance between adjacent antennas that facilitates data or
electrical power transfer can also be adjusted to meet specific
application requirements. As defined herein, the term "tapped"
means an electrical connection between at least two points.
[0022] In at least one of the embodiments of the present
disclosure, a system that includes a single structure multi mode
antenna is provided. The system includes an antenna having a first
conductive wire forming a first coil capable of generating a first
inductance having N.sub.1 number of turns with spaced apart first
and second first coil ends, the first coil is contactable to a
substrate surface. The antenna also includes a second conductive
wire forming a second coil capable of generating a second
inductance having N.sub.2 number of turns with spaced apart first
and second second coil ends, the second coil is positioned within
an inner perimeter formed by the first coil. The antenna further
includes a first terminal electrically connected to the first end
of the first coil, a second terminal electrically connected to the
second end of the second coil and a third terminal electrically
connected along either of the first or second coils. The antenna
also includes wherein a tunable inductance or frequency that is
generatable by selecting a connection between two of the first,
second and third terminals. The system also includes a control
circuit that is electrically connected to at least one of the
first, second and third antenna terminals. The control circuit of
the system is capable of controlling the operation of the
antenna.
[0023] One or more embodiments include wherein the control circuit
comprises at least one of an electrical resistor, a capacitor and
an inductor. One or more embodiments include wherein a gap is
disposed between the inner perimeter of the first coil and an outer
perimeter of the second coil. One or more embodiments include
wherein the gap is at least about 0.1 mm. One or more embodiments
include wherein the first conductive wire or the second conductive
wire comprises two or more filars electrically connected in
parallel. One or more embodiments include wherein the first
terminal is electrically connected to the first end of the first
coil, the first end of the first coil disposed at an end of the
first wire of the first coil located at an outermost first coil
perimeter, the third terminal electrically connected to the first
end of the second coil positioned at a second coil outer perimeter,
and the second terminal is electrically connected to the second end
of the second coil located along an interior perimeter of the
second coil.
[0024] One or more embodiments include wherein a selection circuit
is electrically connected to the first, second, and third terminals
of the antenna, wherein actuation of the selection circuit
electrically connects two of the three terminal ends so that an
antenna operating frequency is modified. One or more embodiments
include wherein the selection circuit comprises at least one of an
electrical component selected from the group consisting of a
resistor, a capacitor, and an inductor. One or more embodiments
include wherein the third terminal of the antenna is electrically
connected to an electrical switch circuit comprising at least one
capacitor, wherein the electrical switch circuit is electrically
connected to the second end of the first coil and the first end of
the second coil, and wherein actuation of the electrical switch
electrically connects two of the three antenna terminal ends so
that an antenna operating frequency is modified. One or more
embodiments include wherein N.sub.1 is at least one and N.sub.2 is
at least two. One or more embodiments include wherein N.sub.2 is
greater than N.sub.1.
[0025] One or more embodiments include wherein each terminal has a
terminal lead portion that extends between a coil connection point
and a terminal end, the coil connection point electrically
connected to either of the first and second conductive wires of the
first and second coils, respectively, and wherein the terminal lead
portion extends over at least a portion of either of the first and
second conductive wires of the first and second coils,
respectively. One or more embodiments include wherein a plurality
of first vias are positioned adjacently along a right side of a
length of the terminal lead portion and a plurality of second vias
are positioned along a left side of the length of the terminal lead
portion and opposed from the plurality of first vias so that each
of the plurality of first vias opposes one of the plurality of
second vias, wherein the respective opposing vias of the plurality
of first and second vias are electrically connected to the same
conductive wire of either of the first or second coils, thereby
establishing a conductive electrical path therebetween that
bypasses the terminal lead portion. One or more embodiments include
wherein at least the first or second coil has a variable wire
width. One or more embodiments include the antenna having a quality
factor greater than 10.
[0026] One or more embodiments include wherein an electrical signal
selected from the group consisting of a data signal, an electrical
voltage, an electrical current, and combinations thereof is
receivable by at least the first and second coils. One or more
embodiments include wherein an electrical signal selected from the
group consisting of a data signal, an electrical voltage, an
electrical current, and combinations thereof is transmittable by at
least the first and second coils. One or more embodiments include
wherein the substrate comprises material composed of an
electrically insulative material selected from the group consisting
of a polyimide, an acrylic, fiberglass, polyester, polyether imide,
polytetrafluoroethylene, polyethylene, polyetheretherketone (PEEK),
polyethylene napthalate, fluropolymers, copolymers, a ceramic
material, a ferrite material, and combinations thereof. One or more
embodiments include wherein the antenna is capable of receiving or
transmitting within a frequency band selected from the group
consisting of about 100 kHz to about 250 kHz, about 250 kHz to
about 500 kHz, 6.78 MHz, 13.56 MHz, and combinations thereof. One
or more embodiments include wherein the antenna is capable of
receiving or transmitting at frequencies of at least 100 kHz.
[0027] In a preferred embodiment, various materials may be
incorporated within the structure of the antenna to shield the
coils from magnetic field and/or electromagnetic interference and,
thus, further enhance the antenna's electrical performance.
Specifically, magnetic field shielding materials, such as a ferrite
material, may be positioned about the antenna structure to either
block or absorb magnetic fields that create undesirable proximity
effects that increase electrical impedance within the antenna. As
will be discussed in more detail, these proximity effects generally
increase electrical impedance within the antenna which results in a
degradation of the quality factor. In addition, the magnetic field
shielding materials may be positioned about the antenna structure
to increase inductance and/or act as a heat sink within the antenna
structure to minimize over heating of the antenna. Furthermore,
such materials may be utilized to modify the magnetic field profile
of the antenna. Modification of the magnetic field(s) exhibited by
the single structure antenna of the present disclosure may be
desirable in applications such as wireless charging. For example,
the profile and strength of the magnetic field exhibited by the
antenna may be modified to facilitate and/or improve the efficiency
of wireless power transfer between the antenna and an electric
device such as a cellular phone. Thus, by modifying the profile
and/or strength of the magnetic field about an electronic device
being charged, minimizes undesirable interferences which may hinder
or prevent transfer of data or an electrical charge
therebetween.
[0028] Thus, the single structure antenna of the present disclosure
is of an efficient design that is capable of operating over
multiple frequencies having an optimized inductance and quality
factor that comprises at least two inductor coils that are
electrically connected in series. The single structure antenna of
the present disclosure enables the antenna to be tuned to a
multitude of customizable frequencies and frequency bands to
facilitate optimized wireless transfer of electrical energy and/or
data.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 illustrates an embodiment of a prior art four
terminal two-structure dual mode antenna.
[0030] FIG. 2 shows an embodiment of a three terminal single
structure multiple mode antenna of the present disclosure
comprising a switch circuit.
[0031] FIG. 2A is an electrical schematic diagram of the three
terminal single structure multiple mode antenna illustrated in FIG.
2.
[0032] FIG. 3 illustrates an embodiment of a three terminal single
structure multiple mode antenna of the present disclosure.
[0033] FIG. 3A is an electrical schematic diagram of the three
terminal embodiment of the antenna shown in FIG. 3.
[0034] FIG. 3B is an embodiment of a first layer of a multi-layer
single structure multiple mode antenna of the present
disclosure.
[0035] FIG. 3C is an embodiment of a second layer of a multi-layer
single structure multiple mode antenna of the present
disclosure.
[0036] FIG. 3D illustrates a magnified view of a portion of an
inductor coil having a plurality of shunted via connections.
[0037] FIG. 3E is an embodiment of a three terminal single
structure multiple mode antenna of the present disclosure in which
the respective terminals are connected to a single filar.
[0038] FIG. 3F is a magnified view showing an embodiment in which
the filars of an inductor coil are electrically bypassing the
terminal lines.
[0039] FIG. 4 is an electrical schematic diagram of the four
terminal antenna embodiment of the present disclosure shown in FIG.
4.
[0040] FIG. 5 shows an embodiment of a single structure multiple
mode antenna of the present disclosure comprising a conductive
filar with a variable width.
[0041] FIGS. 6A-6E illustrate cross-sectional views of different
embodiments of the antenna of the present disclosure with different
ferrite material shielding configurations.
[0042] FIG. 7 is a flow diagram that illustrates an embodiment of a
fabrication process of a single structure antenna of the present
disclosure.
[0043] FIG. 8A illustrates an embodiment of the magnetic field
strengths generated by a single turn coil antenna.
[0044] FIG. 8B illustrates an embodiment of the magnetic field
strengths generated by a two turn coil antenna.
[0045] FIG. 8C illustrates an embodiment of the magnetic field
strengths generated by a three turn coil antenna.
[0046] FIG. 9 shows an embodiment of a two coil antenna fabricated
from a metal stamping process.
[0047] FIG. 10 is a flow chart that illustrates an embodiment of a
fabrication process of a single structure antenna of the present
disclosure having a unitary body structure.
[0048] FIG. 11 shows a theoretical embodiment of a single structure
antenna of the present disclosure comprising n+1 number of
terminals.
[0049] FIGS. 12A-12C illustrate various embodiments of electrical
switch configurations that provide different electrical connections
between inductor coils.
[0050] FIG. 13 is a flow chart that illustrates an embodiment of
operating a single structure antenna of the present disclosure.
DETAILED DESCRIPTION
[0051] In the following description, numerous specific details are
set forth by way of examples in order to provide a thorough
understanding of the relevant teachings. However, it should be
apparent to those skilled in the art that the present teachings may
be practiced without such details. In other instances, well known
methods, procedures, components, and/or circuitry have been
described at a relatively high-level, without detail, in order to
avoid unnecessarily obscuring aspects of the present teachings.
[0052] The antenna and communication system thereof of the present
disclosure provides for improved induction communication, such as
near field communication. More specifically, the antenna of the
present disclosure is of a single structure design that enables
coupled magnetic resonance. Coupled magnetic resonance is an
alternative technology that when appropriately designed, can
provide for increased wireless power transfer and communication
efficiencies and is less dependent of physical orientation and
positioning requirements of prior art antennas. As a result, the
antenna of the present disclosure provides for improved wireless
transfer efficiency and a better user experience.
[0053] The multi-band single structure antenna of the present
disclosure also enables increased transmission range. As will be
discussed in more detail, the structure of the antenna of the
present disclosure enables tuning of the operating frequency. This
enables the operator to quickly modify the receiving antenna's
operating frequency to match the frequency of the transmitted
signal or, alternatively, transmit a signal at an increased
frequency using a frequency multiplier to match the increased
operating frequency of a receiving antenna. Furthermore, the single
structure antenna of the present disclosure may also comprise a
selection circuit which may be capable of conditioning or modifying
the received or transmitted signal. An example of which includes
modifying the operating frequency of the antenna by a frequency
multiplying factor to increase range.
[0054] In addition, the antenna of the present disclosure enables
increased operating frequencies. Operating at a higher frequency
range provides for smaller antenna form factors. For example,
consider a generic transmitting and receiving antenna combination
both operating at a frequency (w) that are spaced a distance d
apart and have a coupling factor, k. The transmitting antenna has a
transmitting antenna inductance (LT.sub.x) and the receiving
antenna has a receiving antenna inductance (LR.sub.x). In this
scenario, the induced voltage at the receiving antenna is given by
the formula:
V.sub.induced.about..omega.k {square root over
(L.sub.TXL.sub.RX)}
[0055] Based on the equation above, if the frequency of operation
(.omega.) is increased, the respective transmitting and receiving
antenna inductances required to produce a similar induced voltage
is reduced, given a similar coupling factor, k. Thus, as a result,
smaller inductors that require less space can be utilized for the
respective antennas. For example, if the form factor, i.e., surface
area of the coils is kept nearly identical having a similar
coupling coefficient, a thinner receiver coil or transmitter coil
may be possible by designing for a reduced receiving or
transmitting inductance because of the increased operating
frequency (.omega.).
[0056] In wearable electronics, where space is at a premium,
operating at a higher frequency and tuning the respective inductors
of the receiving antenna closer to the intended frequency of
transmission provides the potential of increased performance, i.e.,
improved quality factor and increased induced voltages in a smaller
form factor.
[0057] In contrast to the prior art TSMM antenna, the
single-structure multi-mode (SSMM) antenna of the present
disclosure provides an efficient design that enables the reception
and transmission of a multitude of a non-limiting range of
frequencies which includes the frequency specification of the Qi
and Rezence interface standards, in addition to many other wireless
electrical power transfer standards. In addition, the single
structure multi-mode antenna of the present disclosure enables
multiple communication based standards such as, but not limited to,
near field communication (NFC), radio frequency identification
(RFID), multi-mode standard transponder (MST), in addition to a
host of frequency standards that operate at frequencies greater
than about 400 MHz. The physical mechanism of these multiple
"power" transfer and/or "communications" modes may be purely
magnetic, such as via magnetic fields, electromagnetic, such as via
electromagnetic waves, electrical, such as via capacitive
interactions or piezoelectric action. Piezoelectric power transfer
and/or communication modes would generally require a unique
piezoelectric material such as barium titanate, lead zirconate
titanate, or potassium niobate that is able to transduce acoustic
signals to electrical signals and vice versa.
[0058] Specifically, the single-structure multi-mode (SSMM) antenna
of the present disclosure facilitates either or both the
transmission and reception of wirelessly transmitted electrical
power and/or data. The unique design and construction of the SSMM
antenna of the present disclosure, provides an antenna having
optimized electrical performance in a reduced form factor.
[0059] In addition, the single structure antenna of the present
disclosure may also comprise a plurality of materials such as
various ferrite materials to block magnetic fields from adjacent
wire strands of the plurality of coils. Thus, these magnetic
blocking materials shield adjacent wire strands from the adverse
effects of magnetic fields on the propagation of electrical power
and/or electric signals.
[0060] Specifically, the present disclosure provides an antenna
having a single coil structure in which a multitude inductor coils
are electrically connected in series. Such a construction provides
for an antenna having a compact design that enables adjustment or
tuning of the inductance within the antenna which results in the
ability to tune multiple antenna frequencies.
[0061] Turning now to the drawings, FIGS. 2, 2A, 3, 3A, 3B, 3C, 3D,
3E, 4, 4A, 9 and 11 illustrate different embodiments and
configurations of a single structure multi-mode antenna of the
present disclosure. FIG. 2 illustrates an embodiment of a
three-terminal antenna 20 of the present disclosure. As
illustrated, the antenna 20 comprises a substrate 22 on which is
positioned a first, outer coil 24 and a second, interior coil 26.
More specifically, both the first and second coils 24, 26 are
positioned on an external surface 28 of the substrate 22.
[0062] As shown, the first outer coil 24 comprises a first
electrically conductive material 30 such as a trace or filar which
is positioned in a curved orientation with respect to the surface
28 of the substrate 22. In a preferred embodiment, the trace or
filar 30 is positioned in a spiral or serpentine orientation with
respect to the surface 28 of the substrate 22 having "N.sub.1"
number of turns. The second interior coil 26 comprises a second
electrically conductive material 32 such as a trace or filar
positioned in a curved orientation with respect to the surface 28
of the substrate 22. In a preferred embodiment, the second trace or
filar 32 is positioned in a spiral or serpentine orientation with
respect to the surface 28 of the substrate 22 having "N.sub.2"
number of turns.
[0063] In a preferred embodiment as shown in FIG. 2, the second
interior coil 26 is positioned within an inner perimeter formed by
the first outer coil 24. As defined herein, a "turn" is a single
complete circumferential revolution of the electrically conductive
filar positioned on the surface of a substrate. As illustrated in
the example antenna shown in FIG. 2, the first outer coil 24
comprises 3 turns (N.sub.1) and the second interior coil 26
comprises 14 turns (N.sub.2). In a preferred embodiment, the first
outer coil 24 may comprise from about 1 to as many as 500 or more
"N.sub.1" turns and the second interior coil 26 may comprise from
about 1 to as many as 1,000 or more "N.sub.2" turns. In a preferred
embodiment, the number of "N.sub.2" turns is greater than the
number of "N.sub.1" turns. In addition, it is not necessary for the
first and second coils 24, 26 to be constructed having a discrete
number of turns, the coils 24, 26 may also be constructed having a
partial turn or revolution such as a half or quarter of a complete
turn.
[0064] In addition, the conductive filars 30 that form the first
outer inductive coil 24 have a filar width that may range from
about 0.01 mm to about 20 mm. In a preferred embodiment, the width
of the outer inductor coil filars 30 is constant. However, the
width of the first outer inductor conductive filars 30 may vary.
The conductive filars 32 that form the second interior inductive
coil 26 have a preferred width that ranges from about 0.01 mm to
about 20 mm. The second conductive filar 32 may also be constructed
having a constant or variable width. In a preferred embodiment, the
first electrically conductive filars 30 that form the first outer
inductor coil 24, have a width that is greater than the width of
the second electrically conductive filars 32 that form the second
interior inductor coil 26. However, it is contemplated that the
width of the first conductive filars 30 may be about equal to or
narrower than the width of the second electrically conductive
filars 32 that form the second interior inductor coil 26.
[0065] In general, the first outer inductor coil 24 contributes to
the reception and/or transmission of higher frequencies in the MHz
range whereas, the second interior inductor coil 26 contributes to
the reception and/or transmission of frequencies in the kHz range.
The increased perimeter size and typically fewer number of filar
turns that comprise the first outer inductor coil 24, generally
create first coil inductances in the 4.2 pH range, which, thus,
provides reception and/or transmission in the MHz operating
frequency range. In contrast, the increased number of filar turns
and smaller coil diameter of the second interior inductor coil 26
generally create inductances in the 8.2 pH range, which provides
reception and/or transmission in the kHz operating frequency range.
Furthermore, by electrically connecting at least the first and
second inductor coils 24, 26 in series at different locations
thereof, enables the single structure antenna of the present
disclosure to operate at multiple frequencies while encompassing
reduced surface area and a smaller foot print.
[0066] Specifically, the single structure antenna of the present
disclosure comprises a plurality of terminal connections that are
strategically positioned on the first and second inductor coils 24,
26, respectively. This unique antenna design provides for a variety
of tunable inductances which, in turn, provides for a variety of
selectively tunable operating frequencies. In a preferred
embodiment, the single structure antenna can be designed so that it
can operate at multiple frequencies and multiple frequency bands
anywhere between about the 1 kHz range to about the 10 GHz range.
The prior art two structure antenna 10 is not capable of operating
at such multiple frequencies with such a reduced foot print
size.
[0067] FIG. 2 illustrates an example of a three terminal single
structure antenna 20 of the present disclosure. As shown in FIG. 2,
the first outer coil 24 is electrically connected in series to the
second interior coil 26. This electrical connection between the two
coils 24, 26 combines the inductance contributions of both coils,
and portions thereof, in a reduced foot print. FIG. 2A is an
electrical schematic diagram of the antenna 20 shown in FIG. 2. As
shown, the antenna 20 comprises three terminals, a first terminal
34 a second terminal 36, and a third terminal 35. As illustrated,
the first terminal 34 is electrically connected to the first outer
inductive coil 24, the second terminal 36 is electrically connected
to the second interior inductive coil 26, and the third terminal 35
is electrically connected to a second end of the first outer coil
24. Alternatively, the antenna 20 may be constructed having the
first terminal 34 electrically connected to the second inductive
coil 26 and the second terminal 36 electrically connected to the
first inductive coil 24.
[0068] In a preferred embodiment, the antenna 20 may be constructed
with an electrical switch circuit 37 that enables selection of a
desired inductance and operating frequency. More specifically, the
electrical switch circuit 37 enables the detection and analysis of
the electrical impedance of either or combination thereof of the
first and second coils 24, 26. Therefore, based on the detection
and analysis of the electrical impedance, an efficient selection of
the antenna's operating frequency can be achieved based on an
optimized or desired electrical impedance value. In addition, the
selection of the terminal connections may be based on an optimized
or desired inductance value at a desired operating frequency or
frequencies.
[0069] As illustrated in FIG. 2A, the switch circuit 37 is
electrically connected in series between the first and second coils
24, 26. In a preferred embodiment, the switch circuit 37 enables
the selection of a connection between the first and second coils
24, 26, or alternatively, a selection of either of the first or
second coils 24, 26 individually. The third terminal 35 is
electrically connected at point 33 which is an electrical junction
between the first and second coils 24, 26.
[0070] As previously mentioned, the electrical switch circuit 37
preferably comprises at least one capacitor C.sub.1 having a first
capacitance. The at least one capacitor C.sub.1 is preferably
electrically connected along the third terminal 35. In addition,
the switch 37 may also comprise a second capacitor C.sub.2 having a
second capacitance. The second capacitor C.sub.2 is preferably
connected between point 33 and the second interior coil 26.
Inclusion of the at least one capacitor C.sub.1 enables the
detection and analysis of the impedance of either or both coils 24,
26 at an operating frequency. In a preferred embodiment, the
electrical impedance can be determined by the following equation:
X=2.pi.fL, where X is the electrical impedance of the antenna, f is
the operating frequency of the antenna and L is the inductance of
the antenna.
[0071] In a preferred embodiment, the substrate 22 is of a flexible
form, capable of bending and mechanical flexure. The substrate 22
is preferably composed of an electrically insulating material.
Examples of such insulative materials may include but are not
limited to, a paper, a polymeric material such as polyimide,
acrylic or Kapton, fiberglass, polyester, polyether imide,
polytetrafluoroethylene, polyethylene, polyetheretherketone (PEEK),
polyethylene napthalate, fluropolymers, copolymers, a ceramic
material such as alumina, composites thereof, or a combination
thereof. In some situations (e.g when the antenna is constructed
using insulated wire such as magnet wire/litz wire or stamped
metal), the substrate may be the shielding material.
[0072] In a preferred embodiment, at least one of the first, second
and third terminals 34, 36, 35 of the antenna 20 are electrically
connectable to an electronic device 38. The electrical device 38
may be used to modify and/or condition the electrical power,
electrical voltage, electrical current or electronic data signal
received or transmitted by the antenna 20. The electrical energy
received by the antenna may be used to directly power the
electronic device 38. Alternatively, the electrical device 38 may
be used to transmit electrical power and/or a data signal thereof.
The electronic device 38 may comprise, but is not limited to, a
tuning or matching circuit (not shown), a rectifier (not shown), a
voltage regulator (not shown), an electrical resistance load (not
shown), an electrochemical cell (not shown) or combinations
thereof.
[0073] FIG. 3 illustrates an additional embodiment of a three
terminal single structure antenna 40 of the present disclosure.
Similar to the antenna 20 embodiment illustrated in FIG. 2, the
three terminal antenna 40 comprises a first outer coil 42 that is
electrically connected in series to a second interior coil 44. The
electrical connection between the two coils 42, 44 combines the
inductance contributions of each of the coils 42, 44 in a reduced
size and surface area. The addition of a third terminal further
enables the antenna 40 to be tuned to a specific frequency or
multiple frequency bands. Thus, by providing multiple connection
points within and between the outer and interior inductor coils 42,
44 the inductance, and thus, the receiving or transmitting
frequency bands can be instantaneously adjusted without the need to
add or remove inductors. The three terminal antenna design enables
the first and second coils 42, 44 to be strategically connected at
different locations along either or both the first and second coil
42, 44. As a result, the inductance of the antenna 40 can be
modified, i.e., increased or decreased, without increasing the size
of the footprint of the antenna. The antenna 40 of the present
disclosure efficiently utilizes space and substrate surface area to
increase and/or decrease inductance therewithin and, thus, custom
tune the operating frequency or frequency band of the antenna
40.
[0074] The antenna 40 as shown in FIG. 3 comprises three terminals,
a first terminal 46, a second terminal 48, and a third terminal 50,
each having three respective terminal connections 52, 54, and 56.
Each of the terminals is electrically connected at different
terminal connection points of the antenna 40. As shown, the first
terminal 46 extends from a first end 58 of a first trace 60 of the
first outer coil 42. The second terminal 48 extends from a first
end 62 of a second trace 64 of the second inductor 44. The third
terminal 50 extends from a second end 66 of the second trace 64 of
the second coil 44. Thus, the three terminals 46, 48, and 50
provide different connection points between the first and second
inductor coils 42, 44 and portions thereof. Connecting the various
terminals in different combinations thus provides the antenna 40 of
the present disclosure with different adjustable inductances which,
in turn, modifies the operating frequency or operating mode of the
antenna 40. For example, by electrically connecting the first
terminal 46 to the second terminal 48, a first inductance may be
produced that is generally suitable for operation at a first
operating frequency. Electrically connecting the first terminal 46
to the third terminal 50 produces a second inductance that is
generally suitable for operation at a second operating frequency.
Electrically connecting the second terminal 48 to the third
terminal 50 produces a third inductance that is generally suitable
for operation at a third operating frequency. Each of the
inductances that are capable of being generated by the antenna of
the present disclosure is preferably different from each other.
Furthermore, it is contemplated that the antenna may be able to
instantaneously switch from one inductance value to another,
thereby instantaneously changing the antenna's operating
frequency.
[0075] FIG. 3A illustrates an electrical schematic diagram of the
three terminal antenna 40 illustrated in FIG. 3. As shown,
connecting the first terminal 46 and the third terminal 50 provides
a connection to the first outer inductor coil 42 having "N.sub.1"
number of turns. Connecting the second terminal 48 to the first
terminal 46 provides a connection to the second interior inductor
coil 44 having "N.sub.2" number of turns. Lastly, establishing a
connection between the second and third terminals 48, 50 provides
an electrical series connection to both the first outer inductor
coil 42 and the second interior inductor coil 44 having
"N.sub.1"+"N.sub.2" turns. More specifically, FIG. 3A illustrates
an embodiment in which the first inductor coil 42 is electrically
connected in series with the second inductor coil 44. As shown, the
first terminal 46 is electrically connected to the first end 58 of
the first outer inductor coil 42. The second terminal 48 is
electrically connected to the first end 62 of the second inductor
coil 44 at an electrical junction 68 distal of the first inductor
coil first end 58. As illustrated, the third terminal 50 is
electrically connected to a second end 70 of the first inductor
coil 42.
[0076] In a preferred embodiment, the three-terminal antenna design
shown in FIGS. 3 and 3A enables the operation of the antenna in
three different operation modes. As defined herein, an operation
mode is an operating frequency band width. Such modes may include,
but are not limited to the Qi, PMA and Rezence wireless standard
frequencies. Table I shown below, details an example of the
different terminal connection configurations and how they affect
the operation mode of the antenna. More specifically, Table I
illustrates various examples of how the operating frequency of the
antenna may be changed by connecting various terminal connections
together. It is noted that the operating frequencies detailed in
Table I are examples and that the operating frequency bands may be
custom tailored to meet specific requirements. Such customization
can be achieved through designing each coil with a specific number
of turns, a specific trace width, and terminal location points on
each of the first and second coils.
TABLE-US-00001 TABLE I Terminal Mode Operating Frequency
Connections 1 100-250 kHz (Qi and/or PMA) 1 and 2 1 6.78 MHz (A4WP)
1 and 3 2 13.56 MHz (NFC/RFID/ 1 and 3 Proprietary power and data)
2 100-250 kHz (Qi and/or PMA) 2 and 3 3 250-500 kHz (PMA and/or, 2
and 3 proprietary power and data)
[0077] While FIGS. 3 and 3A illustrate a specific example of
connecting three terminals to the respective ends of the first and
second inductor coils 42, 44, it is further contemplated that these
connections may be positioned at various electrically conductive
points along the first and second conductive traces 60, 64 of the
first and second inductor coils 42, 44. In addition, it is
contemplated that additional terminal connections may be positioned
along the first and second 42, 44 inductor coils of the antenna 40,
to further provide customized inductances and, thus, provide
customized operating frequencies of the antenna 40. In general,
establishing an electrical connection with an inductor coil or
multiple inductor coils having an increased number of turns
increases the inductance that results in an antenna that more
suitable to receive or transmit lower frequency signals. Likewise,
establishing an electrical connection with an inductor coil or
multiple inductor coils having a decreased number of turns
decreases the inductance and therefore results in an antenna that
is more suitable to receive or transmit higher frequency
signals.
[0078] Similar to the two terminal antenna illustrated in FIGS. 2
and 2A, the three terminal antenna may be electrically connected to
an electrical device 38. The electrical device 38 may be designed
to condition or modify electrical power and/or an electrical
signal, such as a digital data signal.
[0079] Alternatively, the electrical device 38 may directly receive
or transmit the electrical power and/or data signal. The electronic
device 38 may comprise, but is not limited to, a tuning or matching
circuit (not shown), a rectifier (not shown), a voltage regulator
(not shown), an electrical resistance load (not shown), an
electrochemical cell (not shown) or combinations thereof. In
addition to modifying or conditioning a received electrical
voltage, electrical current, or digital signal, the electronic
device 38 may also be used to modify or condition an electrical
voltage, electrical current, or digital signal that is being
transmitted by the antenna 40.
[0080] FIGS. 3B and 3C illustrate an embodiment of a multiple layer
three terminal antenna 72. In a preferred embodiment, the single
structure antenna of the present disclosure may comprise a
plurality of two or more substrate layers 22 that are positioned in
a parallel orientation to each other. In addition, at least one
electrically conductive trace is positioned along an exterior
surface of the substrates that comprise the antenna 72. The filar
or filars may be orientated such that at least one inductor coil is
disposed along a top surface of one or more of the substrates. The
substrates that comprise the antenna are preferably oriented in the
same orientation such that the bottom surface of a first substrate
is positioned above the top surface of a second substrate.
[0081] In addition, at least one via may be provided to establish
an electrical connection between the various substrate layers. In a
preferred embodiment, the at least one via provides an electrical
connection between filars or portions of filars that comprise an
inductor coil or coils at different substrate layers. As defined
herein a "via" is an electrical connection between two or more
substrate layers. A via may comprise a wire, an electrically filled
through-bore or electrically conductive trace.
[0082] Specifically, FIGS. 3B and 3C illustrate the first and
second layers, respectively of a two layer three terminal single
structure antenna. FIG. 3B illustrates an embodiment of a first or
lower layer 74 of the antenna 72 of the present disclosure. As
shown, the first layer 74 comprises a first outer inductive coil 76
that is electrically connected in series to a second interior
inductive coil 78.
[0083] In a preferred embodiment, as illustrated in FIG. 3B, the
first terminal 46 is electrically connected in parallel to two
traces or filars, thereby creating a bifilar connection 80 that
comprises the first inductor coil 76. It is noted that two or more
adjacent electrically conductive traces or filars that comprise an
inductive coil may be connected in parallel. In general, connecting
two or more adjacent traces or filars reduces electrical
resistance, particularly the equivalent series resistance (ESR) of
the antenna and as a result, improves the quality factor of the
antenna.
[0084] As shown in FIG. 3B, the first inductor coil 76 is
electrically connected in series to the second interior inductor
coil 78 that is positioned within an inner perimeter formed by the
first inductor coil 76. As shown, a second end 82 of the first
inductor coil 76, located at an inner most end of the coil 76 is
electrically connected to a first end 84 of the second inductor
coil 78. The first end 84 of the interior inductor coil 78 is
disposed at the end of an outer most filar track of the second
inductor coil 78. The second inductor coil 78 terminates at a
second inductor coil second end 86 which is disposed at an inner
most location of the second inductor coil 78.
[0085] FIG. 3C illustrates an embodiment of a second upper
substrate layer 88 of the antenna 72 of the present disclosure. The
second layer 88 is preferably positioned directly above the first
lower substrate 74. The second layer 88 comprises a third outer
inductor coil 90 that is electrically connected in series to a
fourth interior inductor coil 92. In a preferred embodiment, the
respective first and third coils 76, 90 and the second and fourth
coils 78, 92 of the first and second layers 74, 88 may be
positioned about their respective substrates in a parallel
relationship. In addition, the respective first and third coils 76,
90 and the second and fourth coils 78, 92 of the first and second
layers 74, 88 may be in a similar position about their respective
substrate surfaces and may comprise the same number of turns with
similar trace widths. Alternatively, the respective first and third
coils 76, 90 and the second and fourth coils 78, 92 of the first
and second layers 74, 88 may be positioned at different locations
relative to their specific substrate surfaces and they may have
differing number of turns with differing trace widths.
[0086] Similar to the first layer 74, the first terminal 46 of the
second layer 74 is electrically connected in parallel to two
adjacently positioned traces or filars, thereby creating a bifilar
connection at a first end 94 of the third inductor coil 90. This
bifilar connection comprises the electrical trace pattern of the
third inductor coil 90, extending around the third coil 90 and
ending at a second end 96 thereof. Furthermore, the third inductor
coil 90 is electrically connected in series to the fourth interior
inductor coil 92 positioned within the inner perimeter of the third
inductor coil 90 at a third inductor coil second end 96 which is
disposed at an interior location of the third inductor coil 90. The
fourth inductor coil 92 is electrically connected to the third
inductor coil 90 at a first end 98 of the interior inductor coil
which is disposed at an outer most filar track of the fourth
inductor coil 92. In addition, as illustrated in FIG. 3C, the
second upper layer 88 also comprises the second and third terminal
connections 48, 50. In a preferred embodiment, the second terminal
48 is electrically connected at a second end 100 of the fourth
inductor coil 92 positioned at an inner most location of the fourth
coil 92. In addition, the length of the second terminal 48 is
electrically isolated from each of the filar tracks that comprise
the third and fourth inductor coils 90, 92. The third terminal 50
is provided on the second upper layer 88. As shown, the third
terminal 50 is electrically connected to the bifilar track 94 that
is disposed at the inner most location of the third outer inductor
coil 90.
[0087] Furthermore, a via 102 or a plurality of vias 102, are
preferably positioned between two or more substrate layers 74, 88
that comprise the single structure antenna 72 of the present
disclosure. More preferably, the at least one via 102 provides a
shunted electrical connection between different locations between
the respective first and third inductor coils 76, 90 or the second
and fourth inductor coils 78, 92 to minimize electrical resistance
which may adversely affect electrical performance and quality
factor.
[0088] In a preferred embodiment, a plurality of shunted via
connections are positioned between the upper and lower layers to
electrically isolate portions of the second and third terminals 48,
50, thereby enabling the terminals to "overpass" the conductive
traces of the respective coils. More specifically, to create an
"overpass" a plurality of vias 102 may be positioned on respective
left and right sides of a trace 104 of the terminal. The plurality
of vias 102 positioned on the respective left and right sides of
the terminal line 104 of the terminal thus form electrical paths
underneath the terminal trace 104, thereby electrically isolating
the terminal trace 104 by "bypassing" the portion of conductive
traces on which the terminal lead 104 is positioned. In addition,
the plurality of shunted vias 102 may also create an electrical
path that bypasses at least a portion of the terminal lead 104. In
this embodiment, each of the plurality of vias 102 are positioned
in opposition to each other on respective left and right sides of
the terminal lead 104.
[0089] FIG. 3D illustrates a magnified view of an example of a
plurality of shunted via connections between a portion of the first
inductor coil 76 that is disposed on the lower first substrate
layer 74 and the third inductor coil 90 that is disposed on the
upper second substrate layer 88. As shown, a plurality of via
connections is shown between inductor coils that are disposed on
the respective upper and lower substrate layers 74, 88. More
specifically, as shown in the embodiment of FIG. 3D, there are four
vias 102 positioned along each filar tracks besides each of the
respective right and left sides of the terminal line 104. In a
preferred embodiment, the via connections provide a shunted
electrical connection that by passes under the terminal line 104.
Thus by positioning a plurality of vias adjacent the respective
sides of the terminal line 104, an electrical connection can be
provided that bypasses the terminal line 104 of the terminal
thereby keeping the terminal trace 104 electrically isolated from
the conductive traces it passes through. Furthermore, by providing
a plurality of vias 102 positioned along each of the filar tracks
that comprise the inductor coil, various electrical connections can
be made which can further tailor the inductance and resulting
operating frequency of the single structure antenna of the present
disclosure. For example, various electrically isolated terminal
connections can be positioned throughout the inductor coils thus
establishing further customized inductances and operating
frequencies.
[0090] FIG. 3E illustrates an alternative embodiment of a single
structure antenna 106 in which respective first and second
inductive coils 108, 110 comprise a single filar pattern. As shown
the first, second and third terminals 46, 48, and 50 are
respectively connected to a single filar that comprises the first
and second inductor coils 108, 110. While it is preferred to
connect the respective terminals to multiple filars, such as the
first terminal connection shown in FIGS. 3B and 3C, to minimize
electrical resistance, it may be necessary to provide an electrical
connection to a single filar to achieve a desired inductance in a
relatively small space and/or surface area. In general, having an
electrical parallel connection to two or more adjacently positioned
filars reduces electrical resistance which in turn increases the
quality factor of the antenna.
[0091] FIG. 3F illustrates a magnified view of the terminal
connections illustrated in FIG. 3E. As shown, the terminal traces
of the second and third terminals 48, 50 are electrically isolated
as they effectively bypass over the electrically conductive the
filar tracks that comprise the inductor coil. Via connections 103
provided on both sides of the respective terminal lines 104 provide
an electrical connection that bypasses the terminal lines thereby
electrically isolating the terminal lines from the filar lines of
that comprise the inductor coil. As shown, a plurality of vias 102A
are positioned on the right side of the terminal lead 104 of the
third terminal 50, vias 102B are positioned to the left and right
of the terminal traces 104 of respective third terminal 50 and
second terminal 48 and vias 102C are positioned to the left of the
terminal trace of the first terminal 48.
[0092] In addition to the two and three terminal antennas
illustrated in the present application, it is further contemplated
that a single structure antenna may comprise four or more terminal
connections. FIG. 4 illustrates an electrical circuit diagram of an
embodiment of a four terminal antenna 112 of the present
disclosure. As illustrated, the first terminal 46 is electrically
connected to the first end 58 of the first outer inductor coil 42.
The second terminal 48 is electrically connected to the first end
of the second inductor coil 44. The third terminal 50 is
electrically connected to the second end 70 of the first inductor
coil 42. In addition, a fourth terminal 114 is electrically
connected to a second point 116 along the electrically conductive
track of the first inductor coil 42. The fourth terminal connection
effectively shortens the length of the first inductor coil 42
and/or the number of turns between electrical connections thereby
providing an additional terminal connection which can be selected
to adjust the inductance and operating frequency of the
antenna.
[0093] Table II shown below, details the inductance and resulting
operating frequency of an exemplar three and four terminal
connection antennas illustrated in FIGS. 2, 2A, 3, 3A, 4 and 4B. It
is noted that the inductance may be increased or decreased by
modifying the number of turns of at least one of the first and
second inductor coils.
TABLE-US-00002 TABLE II Terminal Antenna Connection Operating
Inductance Quality Config Config N.sub.1 N.sub.2 Frequency (.mu.H)
Factor 4 1 and 2 3 0 6.78 MHz 0.84 >110 Terminal 4 3 and 4 0 14
100-300 kHz 6.7 >20 Terminal 3 1 and 2 3 14 6.78 MHz 0.84
>110 Terminal 3 1 and 3 3 17 100-300 kHz 7.5 ~17.5 Terminal 3 2
and 3 3 14 100-300 kHz 6.7 >20 Terminal
[0094] As the table above illustrates, by establishing different
electrical connection points along the coils that comprise the
antenna, provides for a wide range of inductances, operating
frequencies and frequency bands. As shown above, by increasing or
decreasing the total number of turns, i.e. by selectively
connecting different locations of the electrically connected the
first and second inductor coils, and portions thereof affects the
resultant inductance of the antenna.
[0095] In a preferred embodiment, the electrical or electronic
device 38 may be a selection circuit 118 electrically connected to
the single structure antenna of the present disclosure.
Specifically, the selection circuit 118 is electrically connected
to at least two of the terminals that comprise the antenna. The
selection circuit 118 actively monitors and measures the electrical
impedance at the respective antenna terminals and combinations
thereof. Thus, when the electrical impedance is measured to be at,
above, or below a certain threshold electrical impedance or band of
electrical impedances, the selection circuit 118 is capable of
connecting or disconnecting the various terminals that comprise the
antenna to achieve a desired frequency band. In a preferred
embodiment, the selection circuit 118 comprises at least one
capacitor having a capacitance C.sub.3. The capacitance of the
selection circuit is selected to activate a switching mechanism
between antenna terminals by providing a high impedance path or a
low impedance path, depending on the frequency of operation. In
addition, the selection circuit 118 may also be able to actively
connect and/or disconnect various regions or specific locations
along the inductance coils that comprise the single structure
antenna. In an embodiment, the selection circuit 118 operates by
selecting an inductor coil, portion of an inductor coil, or
combinations thereof, having the lowest electrical impedance.
Alternatively, the selection circuit 118 may be designed to
actively switch between terminals at a specific electrical
impedances or range of electrical impedances. For example, the
selection circuit 118 may measure the electrical impedance at
various terminal connections and determine that based on the value
of the capacitance C.sub.3 within the selection circuit 118 to
connect terminals 1 and 3 instead of terminals 1 and 2 for
example.
[0096] Consider, for example, a multi-mode antenna system wherein a
first frequency mode is operating in the frequency range of
f.sub.1+/-.DELTA.f.sub.1, and a second frequency mode is operating
at f.sub.2+/-.DELTA.f.sub.2, wherein f.sub.1 is the resonating
frequency of the first outer inductor coil, .DELTA.f.sub.1 is the
bandwidth of the resonating frequency of the first outer inductor
coil formed by the first terminal 46 and the third terminal 50
(FIG. 3E), f.sub.2 is the resonating frequency of the second
interior inductor coil, and .DELTA.f.sub.2 is the bandwidth of the
resonating frequency of the second interior inductor coil formed
between the first and second terminals 46, 48 (FIG. 3E), provided
the following conditions (A, B, and C) are true for the exemplar
antenna.
Example Conditions:
[0097] f.sub.1.gtoreq.10f.sub.2, A.
.DELTA.f.sub.2.ltoreq.0.5f.sub.2 B.
.DELTA.f.sub.1.ltoreq.f.sub.1/50 C.
[0098] The selection circuit may be configured to select a desired
antenna impedance Z.sub.2, at a desired antenna operating frequency
f. For example, given the parameter equations as shown below, where
C.sub.3 is the capacitance value of the selection circuit 118 for a
desired antenna operating frequency, f (e.g.
f=f.sub.1.+-..DELTA.f.sub.1 or f=f.sub.2.+-..DELTA.f.sub.2) and in
which the impedance of the antenna is multiplied by a constant such
as 1, 2, or 5. Thus, the selection circuit 118 can be designed such
that the terminal connections are made at a certain impedance
threshold value at a specific frequency or frequency band which may
be determined by a multiplier constant.
1 2 .pi. f C 3 < Constant .times. Z 1 or 2 ##EQU00001##
[0099] In general, the greater the difference in electrical
impedance, the better discrimination in coil selection, thus the
multiplier constant such be selected to create a discriminating
electrical impedance that may be used to modify the operating
frequency of the antenna. Thus, provided a capacitance value
C.sub.3, the selection circuit may choose between the lower of the
electrical resistance of the first inductor coil Z.sub.1 and the
electrical resistance of the second inductor coil Z.sub.2. In the
example, if
1 2 .pi. f C 1 ##EQU00002##
is lower than Z.sub.2, the selection circuit may actively choose
the terminal connections for the first inductor coil. An exemplary
situation is when the higher frequency range conforms to a single
mode, the Rezence wireless charging standard operating at a
frequency f.sub.1 of about 6.78 MHz with a bandwidth of +/-15 kHz,
while the lower frequency range conforms to two modes, i.e., the Qi
standard operating between 100 kHz and 205 kHz and the PMA standard
operating between 100 kHz and 350 kHz. In this case, if the first
outer inductor coil is selected, then the antenna will actively
receive or transmit in the Rezence mode at an operating frequency
of about 6.78 MHz.
[0100] In addition to the number of turns and various lengths of
the electrically conductive filars of the respective inductor coils
that control the inductance and operating frequency of the antenna
of the present disclosure, the quality factor of the single
structure multiple mode antenna of the present disclosure can be
significantly affected by the length and position of a gap 120 of
space disposed between adjacent first and second inductor coils
such as the first and second inductor coils 76, 78 and/or the third
and fourth inductor coils 90, 92.
[0101] As will be described herein, the single structure multiple
mode antenna 20, 40, 72, 106, 112 of the present disclosure is
preferably designed with a high quality factor (QF) to achieve
efficient reception/transfer of electrical power and/or an
electrical data signal. In general, the quality factor of the
antenna is increased by reducing the intrinsic resistive losses
within the antenna, particularly at high operating frequencies of
at least 300 kHz.
[0102] The quality factor is the ratio of energy stored by a device
to the energy lost by the device. Thus, the QF of an antenna is the
rate of energy loss relative to the stored energy of the antenna. A
source device carrying a time-varying current, such as an antenna,
possesses energy which may be divided into three components: 1)
resistive energy (W.sub.res), 2) radiative energy (W.sub.rad), and
3) reactive energy (W.sub.rea). In the case of antennas, energy
stored is reactive energy and energy lost is resistive and
radiative energies, wherein the antenna quality factor is
represented by the equation Q=W.sub.rea/(W.sub.res+W.sub.rad).
[0103] In near field communications, radiative and resistive
energies are released by the device, in this case the antenna, to
the surrounding environment. When energy must be transferred
between devices having limited power stores, e.g., battery powered
devices having size constraints, excessive power loss may
significantly reduce the devices' performance effectiveness. As
such, near-field communication devices are designed to minimize
both resistive and radiative energies while maximizing reactive
energy. In other words, near-field communications benefit from
maximizing Q.
[0104] By example, the efficiency of energy and/or data transfer
between devices in an inductively coupled system is based on the
quality factor of the antenna in the transmitter (Q1), the quality
factor of the antenna in the receiver (Q.sub.2), and the coupling
coefficient between the two antennas (K). The efficiency of the
energy transfer varies according to the following relationship:
eff.alpha..kappa..sup.2Q.sub.1Q.sub.2. A higher quality factor
indicates a lower rate of energy loss relative to the stored energy
of the antenna. Conversely, a lower quality factor indicates a
higher rate of energy loss relative to the stored energy of the
antenna. The coupling coefficient (K) expresses the degree of
coupling that exists between two antennas.
[0105] Further, by example, the quality factor of an inductive
antenna varies according to the following relationship:
Q = 2 .pi. fL R ##EQU00003##
where f is the frequency of operation, L is the inductance, and R
is the total resistance (ohmic+rediative). As the quality factor is
inversely proportional to the resistance, a higher resistance
translates into a lower quality factor. Thus, the antenna of the
present disclosure is designed to decrease the electrical
resistance and, therefore, increase the quality factor.
[0106] Specifically, the single structure multiple mode antenna of
the present disclosure is designed with a gap of space 120
positioned between adjacently positioned inductor coils such as the
first and second inductor coils 24, 26. This gap 120 preferably
reduces the proximity effect between adjacently positioned inner
and outer coils, such as 76, 78 (FIG. 3B) and 90, 92 (FIG. 3C). As
defined herein, "proximity effect" is the resultant increase in
electrical resistance that occurs when two wires carrying
alternating current, are positioned next to each other. More
specifically, the proximity effect relates to the effect that one
current carrying filament has on an adjacent current carrying
filament when time-varying current is propagating through at least
one of the conductive filaments. The magnetic field generated by
one filament creates a field that opposes the current in the
adjacent filament, thereby creating additional alternating current
(AC) electrical resistance. This effect increases with frequency
according to Faraday's law. In other words, when two electrically
conductive wires are positioned next to each other, the magnetic
field of one wire induces longitudinal eddy currents in the other
adjacent wire. These eddy currents flow in long loops along the
wire in the opposite direction as the main current. Thus, these
eddy currents reinforce the main current on the side facing away
from the first wire, and oppose the main current on the side facing
the first wire. The net effect is a redistribution of the current
in the cross section of the wire into a thin strip on the side
facing away from the other wire. Since the current is concentrated
into a smaller area of the wire, the resistance is increased.
[0107] The proximity effect has a significant effect on the quality
factor of the antenna design. The applicants have discovered that
the proximity effect can be greatly reduced by increasing the gap
or distance 120 between the first outer and second interior
inductor coils. However, increasing the gap 120 between these coils
such that the proximity effect is negligible appreciably increases
the foot print of the antenna which is not desired.
[0108] Therefore, a balance between the strength of the proximity
effect and its effect on the quality factor and foot print size
must be optimally achieved. In general, the applicants have
discovered that by providing the gap 120 having a distance of about
0.2 mm reduces the magnetic field strength by about 50%, and
designing the gap 120 with a distance of about 1 mm reduces the
magnetic field strength by about 90%. It is contemplated that the
gap 120 may range from about 0.05 mm to about 10 mm.
[0109] Another important consideration is the operating frequency
of the antenna. In general, AC electrical resistance increases with
increasing magnetic field strength. This increase in AC electrical
resistance is about proportional to the magnetic field strength.
This is due to the generally increased proximity effect at
increased operating frequencies. In general, the increase in
proximity effect can be mathematically represented by the strength
of the magnetic field H of an adjacent filar multiplied by the
operating frequency.
[0110] For example, to obtain a similarly equal reduction of
proximity effect for a first antenna operating at 6.78 MHz in
comparison to a second antenna operating at 200 kHz, the magnetic
field strength generated by the first antenna is required to be
reduced by about a factor of 34 (6.78 Mhz/200 kHz). Therefore, to
obtain a similar reduction in AC electrical resistance due to the
proximity effect, between the first antenna operating at 6.78 MHz
and the second antenna operating at 200 kHz, would thus require a
gap of about 0.2 mm between adjacent coil traces for the second
antenna operating at 200 kHz, and a gap greater than 5 mm between
adjacent coil traces for the first antenna operating at 6.78
MHz.
[0111] The applicants have thus discovered that designing the gap
120 having a dimension of 0.5 mm, or greater, between the first
outer and second interior coils significantly reduces the proximity
effect to a negligible amount for frequencies between about 100 to
about 200 kHz. Furthermore, the applicants have discovered that
designing the gap 120 having a distance of about 1 mm for
frequencies between about 200 to about 400 kHz, or greater, is more
preferred. In some cases, where the overall allowable surface area
is large, for example, when the total number of turns of the first
outer and second interior inductor coils is greater than 100 and
the frequency is around 6.78 MHz to 13.56 MHz, this distance can be
as great as 10 mm. In general, a gap distance 120 of about 10 mm
effectively reduces the magnetic field strength and the proximity
effect by about 99 percent.
[0112] Table III shown below, illustrates the effect of the gap
size on the electrical resistance and resulting quality factor.
Specifically, examples 1-4 are of a three terminal single structure
multi-mode antenna having different gap sizes between the first
outer and second interior coils. As illustrated in the table,
increasing the size of the gap to about 1.8 mm, increases the
quality factor by about 35% in comparison to a gap size of 0.2 mm
of the antenna constructed in example 4. If a larger footprint is
possible for the entire antenna structure, this gap size may be
further increased greater than 5 mm which results in an increase in
quality factor of about 42% in comparison to the example 4 antenna
which constructed with a gap size of about 0.2 mm.
[0113] For example, a system with a coupling coefficient of about
0.05 for a system operating at 6.78 MHz, and using the same coil
configuration for the respective receiving and transmitting
antennas with a 1.8 mm gap will yield an antenna to antenna
efficiency improvement of about 16%. In addition, using a gap size
greater than 5 mm would yield an antenna to antenna efficiency
improvement of about 18% given the equation below where K is the
coupling coefficient between a transmitting and receiving antenna,
Q.sub.1 is the quality factor of the receiving antenna, and Q.sub.2
is the quality factor of the transmitting antenna. As defined
herein, "antenna to antenna efficiency" is the percentage of
electrical energy received by a receiving antenna that was
originally transmitted by a corresponding transmitting antenna.
Eff = .kappa. 2 Q 1 Q 2 ( 1 + 1 + ( .kappa. 2 Q 1 Q 2 ) ) 2
##EQU00004##
TABLE-US-00003 TABLE III Gap Freq. Inductance Resistance Quality
Example Size (MHz) (.mu.H) (ohms) Factor 1 >5.0 mm 6.78 3.1 1.30
101.6 2 1.8 mm 6.78 3.1 1.37 96.4 3 1.0 mm 6.78 3.1 1.57 84.1 4 0.2
mm 6.78 3.1 1.85 71.4
[0114] It is important to note that the magnetic field strength is
directly proportional to the strength of the electrical current
being propagated through an adjacent filar. For example, given the
same operating frequency, the strength of the proximity effect
generated from a filar with 1A of electrical current propagated
therewithin is about 100 times greater than if the electrical
current is at 10 mA.
[0115] FIG. 5 illustrates an embodiment of an inductor coil 121
which comprises a conductive filar 123 having a variable filar
width. As shown, at least one of the inductor coils that comprise
an antenna may be constructed having a filar width that ranges from
about 5 mm to about 0.01 mm, more preferably from 0.55 mm to about
0.2 mm. In the preferred embodiment shown, the inductor coil is
constructed having an outer filar width at a first coil end 122
that ranges from about 10 mm to about 1 mm that progressively
becomes narrow as the filar extends towards the center of the
inductor 121. In a preferred embodiment, the filar width at the
second end 124 may range from about 5 mm to about 0.01 mm. Such
thinning of the filar width is desirous to provide an additional
number of turns within a smaller surface area, thereby leading to
an inductance value that is higher than what would have been
achieved with wider traces for all turns. Furthermore, increasing
the number of turns reduces the cross-sectional area of the
filament utilized by the current due to the net proximity effects
of the multitude of filaments. Therefore it is possible that a wide
trace may have regions through which the current density is
significantly reduced. By designing the coil in a manner of
reducing the trace widths, the area utilization is maximized.
Utilization of cross-sectional area is reduced due to proximity
effect with increased frequency and a greater number of traces.
[0116] Constructing a coil with variable trace widths can
significantly increase the inductance of the antenna. For example,
two antennas having the same coil outer dimension of 34.5
mm.times.27 mm and an inner dimension of 15.4 mm.times.7.9 mm were
constructed. The first antenna was constructed with 13 turns at a
constant trace width of about 0.55 mm and a constant gap with
between traces of about 0.2 mm. In comparison, the second antenna
coil was constructed with 13 turns and a constant gap width of
about 0.2 mm between adjacent traces of the coil. However, the
second antenna was also constructed having a variable trace width
that ranged from 0.55 mm to about 0.2 mm in the interior of the
coil. The inductance of the antenna of design 1 having a constant
trace width was measured to be about 4.2 pH. In contrast, the
inductance of the antenna of design 2 with the variable trace width
was measured to be about 8.2 pH, about double the inductance of the
antenna of the first design with the same overall dimensions.
[0117] In a preferred embodiment, the quality factor may also be
increased by incorporating various materials or structures that
prevent or block the magnetic fields that cause the proximity
effect that thus results in increased electrical resistance of
adjoining conductive filars and ultimately results in a decreased
quality factor. One such shielding material are ferrite materials
which have a high permeability that effectively shields inductor
coils from magnetic fields generated from an adjacent inductor coil
or coils. Thus, by shielding the inductive coil from the magnetic
field generated from another coil, reduces the proximity effect
and, thus, increases the quality factor of the antenna.
[0118] The shielding material preferably has the primary function
of providing a low reluctance path to magnetic field lines thereby
reducing the interaction of the magnetic fields with other metallic
objects, especially objects (e.g. batteries, circuit boards) placed
behind the coil assembly. A second function of the shielding
material is preferably to boost the inductance of the coil and,
simultaneously, to increase the coupling between the transmitter
coil assembly and the receiver coil assembly. The latter directly
affects the efficiency of power transfer. The third ancillary
benefit is that it may also improve the Quality Factor of the coil
antenna if the loss tangent of the magnetic material is
sufficiently small. As defined herein, "reluctance" is the
resistance to a magnetic flux.
[0119] FIGS. 6A, 6B, 6C, 6D, and 6E are cross-sectional views
illustrating various embodiments in which an inductor coil having
an electrically conductive trace 30, 32 of a single structure
multi-mode antenna of the present disclosure may be constructed
using materials that shield the conductive traces, i.e., wires of
the coils 24, 26 from magnetic fields. Such shielding materials may
include, but are not limited to, zinc comprising ferrite materials
such as manganese-zinc, nickel-zinc, copper-zinc, magnesium-zinc,
and combinations thereof. These and other ferrite material
formulations may be incorporated within a polymeric material matrix
so as to form a flexible ferrite substrate. Examples of such
materials may include but are not limited to, FFSR and FFSX series
ferrite materials manufactured by Kitagawa Industries America, Inc.
of San Jose Calif. and Flux Field Directional RFIC material,
manufactured by 3M.TM. Corporation of Minneapolis Minn.
[0120] As shown in the various embodiments, three different such
materials, a first material 126, a second material 128 and a third
material 132, each having a different permeability, loss tangent,
and/or magnetic flux saturation density may be used in the
construction of the single structure antenna of the present
disclosure. In a preferred embodiment, the first material 126 may
comprise at least one of the FFSX series of ferrite materials
having a permeability of about 100 to about 120 across a frequency
range of at least 100 kHz to 7 MHz. The second material 128 may
comprise the RFIC ferrite material having a permeability of about
40 to about 60, and the third material 130 may also comprise a
ferrite material or combinations thereof, as previously mentioned.
In a preferred embodiment, the first 126, second 128, or third 130
materials may comprise a permeability greater than 40. More
preferably, the first 126, second 128, or third 130 materials may
comprise a permeability greater than 100. The magnetic flux
saturation density (Bsat) is at least 380 mT.
[0121] FIG. 6A shows an embodiment in which the conductive segments
30, 32 are positioned directly on an exterior surface of the
ferrite materials. As shown, the first and second ferrite materials
126, 128 serve as substrate layers on which the conductive traces
30, 32 are positioned. The third ferrite material 130 is preferably
positioned within a central location between the coil winding. Note
that each conductive segment 30, 32 could represent multiple traces
of the coil turns. Specifically, as shown, first and second outer
segments 131, 135 of the conductive traces 30, 32 are positioned
directly on the surface of a first layer of the first ferrite
material 126 and the third and fourth inner segments 137, 139 of
the conductive trace 30, 32 are positioned directly on the surface
of a second layer of the second ferrite material 128. The second
layer of the second ferrite material 128 is positioned on top of
the first layer of the first ferrite material 126. A third layer of
the third ferrite material 130 is positioned directly on the second
layer of the second ferrite material 128. In a preferred
embodiment, the first, second and third layers of the different
ferrite materials 126, 128, and 130 are positioned such that
magnetic fields 132 generated by the conductive trace 30, 32 are
absorbed by the ferrite materials. Furthermore, the selection of
the ferrite material may be based on the material used to construct
the conductive lines as well as the amount of the current or
voltage flowing therethrough.
[0122] In a preferred embodiment, the various shielding materials
and structures could be used to create a hybrid shielding
embodiment. In a hybrid shielding embodiment, the various shielding
materials are strategically positioned to improve the performance
of the multiple inductor coils which resonate at differing
frequencies. Thus, the shielding materials are positioned to
enhance the multi-mode operation of the antenna 10. For example,
utilizing a ferrite material having an increased permeability of
about 100 to 120, such as the FFSX series material may be used to
optimally shield a coil resonating at 6.78 MHz without degrading
the performance of the other coil resonating at a lower frequency
range of 100 kHz to about 500 kHz. Likewise, utilization of a
ferrite material having a lower permeability such as from about 40
to about 60, like the RFIC material, is preferred because it
enhances operation of a coil resonating in the lower kHz frequency
region without degrading performance of the higher MHz resonating
coil.
[0123] In addition to the specific shielding material, the
positioning of the shielding material is also important to the
optimal operation of the multi-mode single structure antenna of the
present disclosure. For example with reference to FIGS. 6A through
6E, it may be preferred to position the higher permeability ferrite
material near the higher resonating coil, such as the relative
location of the first material 126 as shown in FIGS. 6A-6E.
Similarly, it may be beneficial to position the lower permeability
material near the coil that is resonating in the kHz range such as
the location of the second material 128 The third material 130
could be a material that has similar material properties as the
second material 128 or, alternatively, the third material 130 could
be a ferrite material that has a high magnetic saturation that
preserves the magnetic performance of the other materials in the
presence of a transmitting that comprise a magnet; it also acts as
an attractor to help affixing to transmitting coils that comprise a
magnet.
[0124] FIG. 6B illustrates a different embodiment of the
construction of the antenna of the present disclosure in which the
second ferrite material 128 is positioned within a cavity formed
within the first material 126. In addition, the height of the
second ferrite material layer 128 is greater than the height of the
first layer of the first ferrite material 126.
[0125] FIG. 6C illustrates another alternative embodiment in which
the second ferrite material 128 is positioned within a cavity of
the first ferrite material 126. However, in contrast to the
embodiments shown ion FIGS. 6A and 6B, the height of the respective
first and second ferrite material layers are about the same. FIG.
6D shows yet another embodiment in which the third ferrite material
130 may be positioned within a second cavity positioned within the
second material layer 128. In addition, the second material 128 is
positioned within the first cavity formed within the first layer of
the first material 126. Lastly, FIG. 6E illustrates a fourth
embodiment in which all three materials 126, 128 and 130 are
positioned such that they are of about the same height.
Specifically as shown, the third material 130 is positioned within
the second cavity of the second material layer 128, the second
material 128 is positioned within the first cavity of the first
material layer 126 with all three material layers 126, 128, 130
being of about equal height. Therefore, the various layers of
ferrite material may be positioned at different heights relative to
each other such that magnetic fields 132 generated by adjacent
conductive lines are optimally adsorbed by the ferrite
materials.
[0126] In addition to utilizing three ferrite materials as
previously discussed, it is contemplated that mixtures or compounds
of various ferrite materials may be used to further custom tailor
the desired permeability. Furthermore, the various layers may be
composed of ferrite material mixtures and alloys. It is also noted
that FIGS. 6A-6C represents specific embodiments in which ferrite
materials may be positioned within the structure of the antenna of
the present disclosure. It is contemplated that the various first,
second, and third ferrite materials 126, 128, 130 can be
interchangeably positioned throughout the structure of the antenna
to custom tailor a desired response or create a specific magnetic
field profile.
[0127] It will be appreciated that the multi-mode single structure
antenna of the present application may be formed or made by any
suitable techniques and with any suitable materials. For example,
the antenna coils may comprise suitable metals or metal containing
compounds and/or composites, conductive polymers, conductive inks,
solders, wire, fiber, filaments, ribbon, layered metal combinations
and combinations thereof be used as conductive materials. Suitable
fabrication techniques may be used to place conductors on/in a
substrate, including, but not limited to, printing techniques,
photolithography techniques, chemical or laser etching techniques,
laser cladding, laser cutting, physical or chemical vapor
deposition, electrochemical deposition, molecular beam epitaxy,
atomic layer deposition, stamping, chemical processing, and
combinations thereof. It may also be suitable to fabricate the
multi-mode single-structure antenna with wire-winding techniques
leveraging magnet wires, coated wires, litz wires or other wires
used by those skilled in the art. Electrical property enhancement,
i.e., enhancement of electrical conductivity and substrate
dielectric constant may also be used to achieve the desired
properties for a specific application. For example, enhancement of
electrical conductivity may be achieved through ion implantation,
doping, furnace annealing, rapid thermal annealing, UV processing
and combinations thereof.
[0128] FIG. 7 illustrates a flow chart illustrating an embodiment
of a method of fabricating a single structure multi-mode antenna of
the present disclosure. As shown in the flow chart, in a first step
200 a substrate 22 may be provided. In a second step 202 the first
coil 24 is formed. The first coil 24 may be formed on a surface 28
of a substrate 22 or alternatively, the first coil 24 may be formed
without a substrate 22 using at least any of the fabrication
techniques previously discussed. In a third step 204, the second
coil 26 is formed such that is electrically connected to the first
coil 24. Like the previous step 202, the second coil 26 may be
formed on a surface 28 of the substrate 22 or alternatively, the
second coil 26 may be formed without a substrate 22 using at least
any of the fabrication techniques previously discussed.
Alternatively, the first and second coils 24, 26 may be formed such
that they are contactable to a surface 28 of a substrate 22. In
this case, the first and second coils 24, 26 are removably
contactable to the surface 28 of a substrate 22. For example, the
substrate 22 may provide a temporary mechanical support for the
antenna.
[0129] After the first and second coils 24, 26 have been formed,
either with or without a substrate 22, at least one terminal is
electrically connected to at least one of the first and second
coils 24, 26 (step 206). In an optional fourth step 206, magnetic
shielding materials may be incorporated within the structure of the
antenna. In a fifth step 208, at least one terminal is electrically
connected to at least one of the first and second coils 24, 26. In
an optional sixth step 210, a selection circuit 118 may be
electrically connected to at least one of the terminals or at least
one of the first and second coils 24, 26. In addition, or in lieu
of a selection circuit, an electrical switch 37 may be electrically
connected to at least one of the first and second coils 24, 26 or
at least one terminal.
[0130] FIGS. 8A-8C illustrate various embodiments of magnetic field
intensity profiles as a function of the number of turns that
comprise the coil of the antenna of the present disclosure. As
illustrated, in general, modifying the number of turns of the
inductor affects the shape and profile of the intensity of the
magnetic field. This ability to modify the position and/or strength
of the magnetic field strength that is generated by the antenna can
be desirable in optimizing data and energy transfer. In a preferred
embodiment the strength and profile of the magnetic field can be
custom tailored to meet the dimensions of various electronic
devices. For example, by modifying the number of coils and/or
position of magnetic shielding materials that comprise the single
structure antenna of the present disclosure, the intensity profile
of the magnetic fields that is generated by the antenna can be
modified. It is noted that all the magnetic intensity profiles
8A-8C where taken of single structure antennas having an outer coil
width dimension of about 150 mm and an outer coil length dimension
of about 90 mm. In addition, the profile magnetic field
measurements were taken from about 8 mm away from the outer surface
of the respective antennas. A relative intensity scale lies along
the right side of each of the plots FIGS. 8A-8C. As indicated by
the intensity scale, the strongest magnetic field intensity has a
relative intensity of about 1 and is graphically represented having
the darkest shade of black. The weakest magnetic field strength has
a relative intensity of about 0.1 and is shown having the lightest
shade of grey.
[0131] FIG. 8A illustrates an embodiment of a magnetic field
intensity profile taken of a single structure antenna comprising
one outer coil having one turn. The magnetic field intensity is
greatest along the outer perimeter of the coil as illustrated by
the darker shades of black which represent the strongest magnetic
field intensity. While the strongest magnetic field intensities are
along the outer perimeter, the weakest magnetic field intensity,
represented by the lighter shade of grey, lies in the central area
formed within the perimeter of the coil. Thus, this embodiment is
optimally configured for wireless energy transfer along the outer
perimeter of the antenna.
[0132] FIG. 8B illustrates an embodiment of a magnetic field
intensity profile taken of a single structure antenna comprising a
coil having two turns. As shown, the greatest magnetic field
intensity lies more along an inner portion of the coil as compared
to the field magnetic field intensity profile of a coil having one
turn as shown in FIG. 8A. The weakest field intensities of the two
turn coil, shown by the lighter shade of grey, lie along the outer
perimeter of the second turn of the coil which is positioned
towards the interior of the antenna. In comparison to the coil
having one turn as illustrated in FIG. 8A, the magnetic field along
the central area of the antenna comprising a coil having two turns
has an overall increased magnetic field. Thus, as shown, adding an
additional interior turn moves the greatest field intensities
closer to the middle of the antenna.
[0133] FIG. 8C illustrates an embodiment of a magnetic field
intensity profile taken of a single structure antenna comprising a
coil having three turns, a first outer turn, a second inner turn
and a third inner most turn. Similar to the antenna comprising a
coil with two turn, the magnetic field intensity of the three turn
coil antenna shown in FIG. 8C is the strongest, along the inner
perimeter of the third innermost coil and central area of the
antenna. Thus, the antenna comprising a coil having three turns has
the strongest magnetic field in general in the central area of the
antenna. In addition, the respective corner locations of the second
inner turn of the coil also has increased magnetic field intensity.
Therefore, such an antenna with a three turn coil is optimally
designed to transfer electrical power and data in the central area
of the antenna.
[0134] FIG. 9 illustrates a further embodiment of an antenna 140 of
the present disclosure of a one piece construction having a unitary
antenna body. As illustrated, the antenna 140 is preferably formed
from one piece of wire or filament 142 that is formed into the
shape of the unitary body antenna 140 extending from a first wire
end 149 to a second wire end 153. In a preferred embodiment, the
antenna 140 may be formed by a stamping process in which the
electrically conductive material is formed together in a mold and
die stamp forming process using a metal blank. In a preferred
embodiment, the metal blank is positioned between the mold and die.
The die is pressed against the metal blank within the mold thus
forming the antenna body 140. In addition, the electrically
conductive material that forms the unitary antenna body may be a
metal bar, wire, or filament that is stamped out of a sheet of
metal. Alternatively, antenna 140 may be formed by a wound wire
process whereby the unitary body of the antenna 140 is formed from
a single wire that is curved or wound into the desired shape of the
antenna 140 comprising a plurality of turns.
[0135] The antenna 140 is preferably formed of a continuous wire
form having multiple electrical connection points 148, 150, 152
that are disposed along various portions of the wire 142 of the
antenna 140. The plurality of electrical connection points 148,
150, 152 or electrical "taps" create multiple inductor coils having
different inductances that comprise the antenna 140 of the present
disclosure.
[0136] As illustrated in FIG. 9, a first electrical connection
point 148 that is disposed at the first end 149 of the wire 142 of
the antenna 140 serves as the common electrical connection. A
second electrical connection point 150 is positioned along the
third turn of the antenna 140 serves as the "low" inductance
electrical connection. A third electrical connection point 152 is
disposed at the second end 153 of the antenna 140 serves as the
"high" inductance electrical connection of the antenna 140. In an
embodiment, terminal leads 154, 156, 158, such as electrically
conductive wires, may be attached to these electrical connection
points to create antenna terminals. Thus, as shown, the first
electrical connection point 148 may serve as the first terminal 34,
the third electrical connection point 152 may serve as the second
terminal 36 and the second electrical connection point 150 may
serve as the third terminal 35. Furthermore, the various first,
second and third electrical connection points 148, 150, 152 form
the multiple inductor coils of the antenna 140. As illustrated, a
first outer inductor coil portion 144 having N.sub.1 number of
turns is disposed between the first and second electrical
connection points 148, 150 and a second inductor coil portion 146
having N.sub.2 number of turns is disposed between the second and
third electrical connection points 150, 152. Similar to the
previous single structure antenna embodiments, the unitary body
antenna 140 may comprises more than three terminal connections
which can be electrically connected to generate a multitude of
operating frequencies and/or inductances. In addition, a turn gap
161 may be positioned between adjacent turns of the first and
second inductor coils portions 144, 146. Specifically, the turn gap
161 is a space disposed between adjacent wires 142 of the antenna
140. In a preferred embodiment, the turn gap 161 may extend from
about 0.1 mm to about 50 mm.
[0137] Preferably, the unitary body antenna 140 illustrated in FIG.
9 is self-standing and does not require the support of a substrate.
However, it is contemplated that such an antenna structure may be
contactable to a substrate surface. Substrates may include, but are
not limited to, a dielectric material and/or a magnetic field
blocking material such as a ferrite material as previously
discussed. In addition, such an antenna construct may be
incorporated within an article of clothing, furniture, an
electrical appliance or a vehicle.
[0138] FIG. 10 is a flow chart that illustrates an embodiment of
method of fabricating the single structure multi-mode antenna 140
having a unitary antenna body. As shown in the flow chart, in a
first step 212, a metal blank is provided. In a second step 214, a
die and mold that are used to form the metal blank into the form of
the antenna 140 are provided. In a third step 216, the die is used
to form the blank metal into the form of the unitary body antenna
140. In a fourth step 218, at least one terminal is electrically
connected to at least one of the first and second coil portions
144, 146. In an optional fifth step 220, a selection circuit 118
may be electrically connected to at least one of the terminals or
at least one of the first and second coil portions 144, 146. In
addition, or in lieu of a selection circuit 118, an electrical
switch 37 may be electrically connected to at least one of the
first and second coil portions 144, 146 or at least one
terminal.
[0139] It is further contemplated that the various embodiments of
the single structure antenna of the present disclosure may comprise
a plurality of terminals greater than three. FIG. 11 illustrates a
theoretical example in which a single structure antenna of the
present disclosure may comprise a plurality of n+1 number of
terminal connections. As shown, the antenna of the present
disclosure may comprise three, four, five or more terminal
connections which can be electrically connected to generate an
infinite number of operating frequency bands and/or
inductances.
[0140] FIG. 11 illustrates a theoretical example of a single
structure antenna of the present disclosure that comprises an
indefinite number of inductors, Ln in which each of the multitude
of inductors may have a different inductance. Furthermore, as
illustrated, the respective inductors, L.sub.1 through L.sub.n
preferably comprise a terminal connection T.sub.1 through
T.sub.(n+1) or electrical "tap" that is electrically connected to
at least a portion of the respective inductor coil. Therefore, it
is possible to create a single structure antenna that may be
selectively tuned to exhibit an unlimited number of frequencies
and/or inductances such that the antenna of the present disclosure
can be tuned to an exact frequency or frequencies.
[0141] FIGS. 12A-12C illustrate embodiments of electrical switch
configurations 160 that may be used to electrically connect and/or
disconnect the various terminals that may comprise the single
structure antenna of the present disclosure. It is noted that FIGS.
12A-12C correlate to respective embodiments illustrated in FIGS.
8A-8C. As illustrated in FIGS. 12A-12C, the exemplar antenna
comprises three inductors L.sub.1-L.sub.3 having four terminal
connections T.sub.1-T.sub.4. A multiple of electrical connection
points 162A-162P are positioned at various locations along the
antenna. In addition, the antenna comprises a multitude of
electrical switches 164, 166, 168, 170, 172, 174, 176 and 178 that
are positioned along the antenna and are designed to electrically
connect and/or disconnect the various electrical connection points
along the antenna. For example, electrical switch 164 is shown
electrically connecting electrical connection points 162A and 162B,
electrical switch 172 is shown electrically connecting electrical
connection points 162M and 162N. Thus, by electrically connecting a
certain combination of electrical connection points 162A-162P along
the single structure antenna by at least one of the various
electrical switches 164-178 the antenna can be tuned to a desired
operating frequency, frequencies and/or inductances that are
suitable to wirelessly transfer or receive electrical energy and/or
data signals as desired.
[0142] Furthermore, any of these multitude of switches may be
turned electrically "on" or "off" as desired as the antenna
operates. It is noted that electrically active, i.e., electrically
connected, electrical connection points are illustrated as black
filled circles whereas non-active electrical connection points,
i.e., electrical connection points that are electrically
disconnected, are shown as unfilled circles. It is further noted
that a microprocessor (not shown) or circuit board (not shown) may
be used to control the combination of switches that are turned "on"
or "off". In addition, the electrical switch may comprise a
multitude of different electrical switches. Examples of which may
include, but are not limited to, an electrical toggle switch, a
rocker switch, a push button switch, an inline switch, switched
capacitor networks, and filter networks that utilize inductors
and/or capacitors. As defined herein, an electrical switch is an
electrical component that can either connect or disconnect an
electrical current, voltage, signal or combinations thereof, along
an electrical pathway. A switch can also divert an electrical
current, voltage, signal or combinations thereof, from one
electrical conductor to another. An electrical switch that is in an
"on" position is defined as allowing an electrical signal or
electrical current or voltage to pass therethrough and thus is
electrically connected. An electrical switch that is in an "off"
position is defined as prohibiting an electrical signal or
electrical current or voltage to pass therethrough and thus is
electrically disconnected.
[0143] FIG. 12A illustrates an embodiment in which the antenna of
the present disclosure is configured with the first and fourth
terminals T1, T4 electrically connected such that the antenna
exhibits an inductance equal to the combination of the first,
second and third inductors L.sub.1, L.sub.2 and L.sub.3.
Specifically, as illustrated, electrical switches 164, 166, 172 and
178 are closed and electrical connection points 162A, 162B, 162C,
162D, 162M, 162N, 1620 and 162P are electrically closed thereby
allowing electrical current to pass therethrough.
[0144] FIG. 12B shows an embodiment in which the antenna is
configured with the first and second terminals T1, T2 electrically
connected so that the antenna exhibits an inductance comprising the
first inductor L.sub.1. Specifically, as illustrated, electrical
switches 164, 166, and 170 are electrically closed and electrical
connection points 162A, 162B, 162C, 162E, 162F, and 162H are
electrically active. All other electrical switches and electrical
connection points are illustrated to be electrically open.
[0145] FIG. 12C shows an embodiment of the antenna in which the
first and third inductors L.sub.1, L.sub.3 that comprise the
antenna are electrically connected. As illustrated, an electrical
switch connections bypass the second inductor L.sub.2 within the
antenna. A first bypass switch electrically connects the first
inductor to a bypass portion of the antenna and a second bypass
switch electrically connects the first inductor L.sub.1 to the
third inductor L.sub.3. Specifically, as illustrated, electrical
switches 164, 168, 174 and 178 are electrically closed and
electrical connection points 162A, 162B, 162C, 162E, 162F, 162G,
162I, 162K, 162L, 162N, 1620 and 162P are electrically active. FIG.
13 is a flow chart that illustrates an embodiment of operating the
multi-mode single structure antenna of the present disclosure. As
shown, in a first step 222, a multi-mode single structure antenna
of the present disclosure is provided. In a second step 224, a
connection between at least two terminals is selected. Thus, by
connecting two of the at least three terminals enables an operator
to select a desired receiving or transmitting antenna frequency. In
addition, by connecting two of the at least three terminals enables
an operator to select a desired inductance that is exhibited by the
antenna. To tune the antenna to a different frequency or
inductance, a second connection between two of the at least three
terminals having a different electrical connection configuration of
that of the first is made. The electrical connections between
terminals may be made manually or alternatively, can be made
automatically by a machine such as a computer or device comprising
a processing unit. As previously mentioned, the electrical
connections between terminals can be made via an electrical switch
37 and/or a selection circuit 118. Thus, it is contemplated that
the single structure antenna of the present disclosure is capable
of being tuned to a plurality of unlimited frequencies or
inductances by connecting different terminals or electrical points
positioned along at least the first and second coils 24, 26. It is
appreciated that various modifications to the inventive concepts
described herein may be apparent to those of ordinary skill in the
art without departing from the spirit and scope of the present
disclosure as defined by the appended claims.
[0146] As used herein, the phrase "at least one of" preceding a
series of items, with the term "and" or "or" to separate any of the
items, modifies the list as a whole, rather than each member of the
list (i.e., each item). The phrase "at least one of" does not
require selection of at least one of each item listed; rather, the
phrase allows a meaning that includes at least one of any one of
the items, and/or at least one of any combination of the items,
and/or at least one of each of the items. By way of example, the
phrases "at least one of A, B, and C" or "at least one of A, B, or
C" each refer to only A, only B, or only C; any combination of A,
B, and C; and/or at least one of each of A, B, and C.
[0147] The predicate words "configured to", "operable to", and
"programmed to" do not imply any particular tangible or intangible
modification of a subject, but, rather, are intended to be used
interchangeably. In one or more embodiments, a processor configured
to monitor and control an operation or a component may also mean
the processor being programmed to monitor and control the operation
or the processor being operable to monitor and control the
operation. Likewise, a processor configured to execute code can be
construed as a processor programmed to execute code or operable to
execute code.
[0148] A phrase such as "an aspect" does not imply that such aspect
is essential to the subject technology or that such aspect applies
to all configurations of the subject technology. A disclosure
relating to an aspect may apply to all configurations, or one or
more configurations. An aspect may provide one or more examples of
the disclosure. A phrase such as an "aspect" may refer to one or
more aspects and vice versa. A phrase such as an "embodiment" does
not imply that such embodiment is essential to the subject
technology or that such embodiment applies to all configurations of
the subject technology. A disclosure relating to an embodiment may
apply to all embodiments, or one or more embodiments. An embodiment
may provide one or more examples of the disclosure. A phrase such
an "embodiment" may refer to one or more embodiments and vice
versa. A phrase such as a "configuration" does not imply that such
configuration is essential to the subject technology or that such
configuration applies to all configurations of the subject
technology. A disclosure relating to a configuration may apply to
all configurations, or one or more configurations. A configuration
may provide one or more examples of the disclosure. A phrase such
as a "configuration" may refer to one or more configurations and
vice versa.
[0149] The word "exemplary" is used herein to mean "serving as an
example, instance, or illustration." Any embodiment described
herein as "exemplary" or as an "example" is not necessarily to be
construed as preferred or advantageous over other embodiments.
Furthermore, to the extent that the term "include," "have," or the
like is used in the description or the claims, such term is
intended to be inclusive in a manner similar to the term "comprise"
as "comprise" is interpreted when employed as a transitional word
in a claim. Furthermore, to the extent that the term "include,"
"have," or the like is used in the description or the claims, such
term is intended to be inclusive in a manner similar to the term
"comprise" as "comprise" is interpreted when employed as a
transitional word in a claim.
[0150] All structural and functional equivalents to the elements of
the various aspects described throughout this disclosure that are
known or later come to be known to those of ordinary skill in the
art are expressly incorporated herein by reference and are intended
to be encompassed by the claims. Moreover, nothing disclosed herein
is intended to be dedicated to the public regardless of whether
such disclosure is explicitly recited in the claims. No claim
element is to be construed under the provisions of 35 U.S.C. .sctn.
112, sixth paragraph, unless the element is expressly recited using
the phrase "means for" or, in the case of a method claim, the
element is recited using the phrase "step for."
[0151] Reference to an element in the singular is not intended to
mean "one and only one" unless specifically so stated, but rather
"one or more." Unless specifically stated otherwise, the term
"some" refers to one or more. Pronouns in the masculine (e.g., his)
include the feminine and neuter gender (e.g., her and its) and vice
versa. Headings and subheadings, if any, are used for convenience
only and do not limit the subject disclosure.
[0152] While this specification contains many specifics, these
should not be construed as limitations on the scope of what may be
claimed, but rather as descriptions of particular implementations
of the subject matter. Certain features that are described in this
specification in the context of separate embodiments can also be
implemented in combination in a single embodiment. Conversely,
various features that are described in the context of a single
embodiment can also be implemented in multiple embodiments
separately or in any suitable subcombination. Moreover, although
features may be described above as acting in certain combinations
and even initially claimed as such, one or more features from a
claimed combination can in some cases be excised from the
combination, and the claimed combination may be directed to a
subcombination or variation of a subcombination.
* * * * *